Low-permeability connecting device

ABSTRACT

A low permeability coupling device for coupling a first endpiece ( 3 ) extending a tube ( 2 ) with a second endpiece ( 10 ) carried by the wall ( 1 ) of a member to which the tube ( 2 ) is connected, in which the second endpiece ( 10 ) has two substantially coaxial walls ( 11, 12 ) defining between them a blind annular housing ( 13 ) for receiving the first endpiece ( 3 ), and a sealing element ( 15 ) extending between the inside face ( 11   a ) of the outer wall ( 11 ) of the second endpiece and the outside surface ( 8 ) of the first endpiece when it is in place in the above-mentioned housing ( 13 ).

This application is the national phase under 35 U.S.C. § 371 of PCTInternational Application No. PCT/FR00/03401 which has an Internationalfiling date of Dec. 6, 2000, which designated the United States ofAmerica.

The present invention relates to a coupling device, in particular aquick coupling provided with means for ensuring that escapes into theatmosphere of substances or certain ingredients thereof flowing throughthe coupling are kept to within limits that are acceptable given thepresent or forthcoming standards and regulations that are in force inthe field of motor vehicles.

BACKGROUND OF THE DISCLOSURE

In motor vehicle engines, fluids (fuel, cooling liquid, air conditioningliquid, hydraulic liquid for power assistance, windscreen washingliquid, . . . ) are transported by pipes to and from pumps and tanks viaducts made of synthetic material that are connected to functionalmembers by means of a variety of connection devices.

The present trend for making such connections is to make use ofso-called “quick” couplings which comprise rigid endpieces ofcomplementary shapes, one secured to the duct and the other secured tothe functional member, with one being engaged in the other and bothbehind held together by some kind of automatic latch.

There is necessarily a degree of functional clearance between theseendpieces in order to enable them to be connected and disconnectedeasily, and in particular without using tools, and this clearance needsto be sealed in order to avoid leakage.

The sealing members used are quite effective with respect to the liquidsthat are transported, but these liquids contain multiple components,some of which are highly volatile and get round the seals that are putinto place. The fluid circuit at this location is therefore morepermeable than it is elsewhere, and it is in such coupling zones thathigh rates of emission to the atmosphere are observed, which emissioncan make the entire circuit unsuitable for complying with the prescribedstandards or recommendations.

OBJECTS AND SUMMARY OF THE INVENTION

The present invention seeks to remedy this drawback by fitting couplingdevices with means for controlling emissions of pollutants (inparticular hydrocarbons) via couplings.

To this end, the invention provides a low permeability coupling devicefor coupling a first endpiece extending a tube with a second endpiececarried by the wall of a member to which the tube is connected, in whichthe second endpiece has two substantially coaxial walls defining betweenthem a blind annular housing for receiving the first endpiece, a sealingelement extending between the inside face of the outer wall of thesecond endpiece and the outside surface of the first endpiece, and theinside surface of the first endpiece being in contact with the outsideface of the inner wall of the second endpiece when said first endpieceis placed in the above-mentioned housing.

Naturally, it is assumed that the inside wall of the second endpiececo-operates in relatively leaktight manner with the inside face of thewall of the second endpiece, as in any coupling, with this beingachieved by using a gasket or otherwise. The disposition of theinvention is such that the housing which receives the first endpiecebetween the two walls of the second endpiece constitutes a chamber forconfining emissions of substances that pass through the first seal. Inthis chamber, the substances tending to escape are in the form of vaporand can condense. Their pressure is well below the pressure that existsin the duct passing through the two endpieces, so these substances havemuch less tendency to escape towards the outside than they do to passthrough the first seal. This tendency can then be countered by gasketswhich are much more effective than those implemented in known couplingdevices or couplers.

In a preferred embodiment, provision can be made for the blind end ofthe annular housing to be situated completely on one side of the wall ofthe member which carries the second endpiece, and preferably beside itsinside face so that if the wall of this housing is permeable (because itis made of a synthetic material and all synthetic materials arepermeable to hydrocarbons or to alcohol-containing substances in motorvehicle fluids), then the substances passing through this wall willreturn to the inside space of the functional member whether it isconstituted by a fuel tank, a fuel pump, . . . This implements a kind ofrecycling for substance that would otherwise tend to escape to theatmosphere.

BRIEF DESCRIPTION OF THE DRAWINGS

Other characteristics and advantages of the invention appear from thedescription given below by way of example and with reference to theaccompanying drawings, in which:

FIG. 1 is a longitudinal section diagram showing the principle of theinvention;

FIG. 2 is an exploded perspective view showing an embodiment of acoupling device of the invention; and

FIG. 3 is a partially cutaway perspective view of the device of theinvention in the coupled-together state.

MORE DETAILED DESCRIPTION

FIG. 1 shows the wall 1 of a functional member which can be, forexample, a tank, a pump, . . . and which is to be connected to a tube 2.The tube 2 is extended by a rigid endpiece 3 with which it is firmlyassociated by any conventional device such as forced engagement on aserrated spigot 4 as shown.

The endpiece 3, which naturally has an axial inside passage 5, isterminated remote from the spigot 4 by an annular wall 6 defined by aninside surface 7 and an outside surface 8. The surfaces 7 and 8 areshown here as being coaxial about the central passage 5 of the endpiece,however the endpiece could constitute a bend with its surfaces extendingdifferently relative to the passage.

The wall 1 of the functional member also has an endpiece 10, whichendpiece has two coaxial walls 11 and 12 defining between them a blindhousing 13 for receiving the portion 6 of the endpiece 3, this housingthus being closed by an end wall 14. The inner wall 12 of the endpiece10 possesses an outside face 12 a; the outer wall 11 of the endpiece 10has an inside face 11 a. Between the outside face 8 of the endpiece 3and the inside face 11 a of the wall 11 of the endpiece 10, there is asealing device 15 and one particular embodiment thereof is described ingreater detail with reference to the following figures. The co-operationbetween the outside surface 12 a of the inner wall 12 and the insidesurface 7 of the portion 6 of the endpiece 3 is leaktight cooperation,with or without a gasket. When the coupling is not a coupling thatprovides instant connection merely by moving the two endpieces together,co-operation between the surfaces 12 a and 7 can be implemented, forexample, by means of a thread and tapping with a gasket being placedbetween the two pieces. For a quick coupling, this co-operation takesplace via another gasket, and a particular embodiment thereof is shownin the figures below.

Like the endpiece 3, the endpiece 10 has an inside passage 16 for thefluid that circulates from the tube 2 towards the functional member, orin the opposite direction. The point of greatest permeability in thehydraulic circuit including this coupling is naturally the space thatexists between the surfaces 12 a and 7. It will be understood that withthe invention, this space leads to the blind housing 13 whichconstitutes a chamber for confining and accumulating any substance thathas managed to get past the sealing between the two surfaces 12 a and 7.In this confinement space, the substance is at a pressure that is lowerthan its pressure inside the pipe conveying the substance, so thesealing system 15 is much more effective than the same system would beif it were to be placed directly between the surfaces 7 and 12 a. Thesubstance can thus stagnate in this housing 13, and if the wall 11, 12,and 14 of the housing 13 is permeable, it can flow through this wall.That is why it is advantageous to provide for the endpiece 10 to belocated on the side of the wall 1 of the functional member that is onthe inside of this member, which might be a tank or a pump, for example,so that any substance which leaves the blind housing 13 through its wallreturns to the functional member instead of going to the atmosphere.

In FIGS. 2 and 3, the embodiment shown relates to a coupling device ofthe quick-coupling kind. The elements of this device that are alreadydescribed above with reference to FIG. 1 have the same references.

The endpiece 10 which is shown here in the form of a piece that isseparate from the functional member to which it is to be fitted, whichseparate piece can be fitted to said functional member by anyconventional means such as bonding by ultrasound, by vibration, byrotation, or by adhesive . . . (the endpiece being fixed to a wall 1 ofthe member that is represented diagrammatically by chain-dotted lines inFIG. 3). The endpiece 10 thus has a portion which is situated on oneside of the wall 1 that essentially constitutes the blind housing 13which is located inside the functional member, while it has anotherportion remote from the housing 13 that projects outside the wall 1 andcarries a resilient clip 17 in conventional manner with its prongspenetrating into slots 18 of the endpiece 10 so as to constituteresilient latches for engaging the endpiece 3 when it is engaged in theendpiece 10. The branches of the clip 17 are initially spaced apart bythe conical portion of the surface 8 of the endpiece 3 as it passes overthem in the slots 18, and then beyond the gasket 15 these branchesspring resiliently into a groove 19 provided in the endpiece 3.

In FIGS. 2 and 3 it can be seen that the sealing device 15 isconstituted by an elastomer material received in an outside groove inthe surface 8 of the endpiece 3. Similarly, there is a sealing device 20formed of elastomer material received in an inside groove in the insidesurface 7 of said endpiece 3. Preferably, the endpiece 3 is made bytwo-material injection so that the gaskets 15 and 20 are formedintegrally with the endpiece 3.

1. A low permeability coupling device in an engine for coupling a tube(2) extended by a first endpiece (3) with a second endpiece (10) carriedby the wall (1) of a member to be connected to the tube, the secondendpiece (10) having two substantially coaxial walls (11, 12) definingbetween them a blind annular housing (13) for receiving the firstendpiece (3), wherein an elastomeric sealing element (15) extendsbetween the inside face (11 a) of the outer wall (11) of the secondendpiece and the outside surface (8) of the first endpiece, while theinside surface (7) of the first endpiece has an elastomeric sealingelement (20) in contact with the outside face (12 a) of the inner wall(12) of the second endpiece when said first endpiece is placed in theabove-mentioned housing (13), and further wherein said blind annularhousing (13) confines hydrocarbon emissions.
 2. A device according toclaim 1, wherein the first endpiece (3) co-operates with the housing(13) of the second endpiece (10) to define an empty space for confiningemissions of substances that occur between the inner wall of the secondendpiece and the first endpiece.
 3. A device according to claim 1,wherein the blind end of the annular housing (13) is located inside themember, the wall of which carries the second endpiece (10).
 4. A deviceaccording to claim 1, including means (17, 18, 19) for releasablysecuring the connection between the first and second endpieces.
 5. Adevice according to claim 1, wherein the second endpiece (10) is anelement fitted to the wall (1) of the member by any connection means. 6.A device according to claim 1, wherein said sealing elements (15, 20)include at least one elastomeric sealing gasket (20) facing towards theinner wall (12) of the second endpiece and at least one elastomericsealing gasket (15) facing towards the outer wall (11) of the secondendpiece, the first endpiece (3) and the gaskets (15, 20) being formedas a single piece obtained by a two-material injection method.